1. Technical Field
The present invention relates to an image reading device and an image reading method used therein.
2. Field of Invention
For existing contact-image-sensor (CIS) scanners, which include a plurality of sensor chips therein, the speed with which images are read can be increased by providing a plurality of output channels therein and outputting image data from the plurality of sensor chips in parallel through the plurality of output channels (refer to, for example, JP-A-2001-94785).
On the other hand, increasing the number of output channels in this way leads to disadvantages in that the complexity of data processing increases and the quality of read images is degraded due to electric crosstalk generated among the plurality of output channels.
Further, the increase of the speed with which images are read is likely to be more frequently demanded by users in the case of reading images at a low-resolution (which is less than 600 dpi), but is likely to be not so frequently demanded by users in the case of reading images at a high-resolution, and thus, it is not necessary to continue the parallel outputting of image data in the case of reading images at a high-resolution.
However, in the existing CIS scanners which are designed so as to enable the parallel outputting of image data, since the parallel outputting of image data is uniformly performed regardless of the resolution, it is difficult to flexibly adapt to the users' demands.